Destroying missiles such as tactical ballistic missiles, airborne targets such as cruise missiles, aircraft, re-entry vehicles, and other targets falls into three primary classifications: “hit-to-kill” vehicles, blast fragmentation warheads, and kinetic energy rod warheads.
“Hit-to-kill” vehicles are typically launched into a position proximate a target via a missile such as the Patriot, Trident or MX missile. The kill vehicle is navigable and designed to strike the re-entry vehicle to render it inoperable. Countermeasures, however, can be used to avoid the “hit-to-kill” vehicle. Moreover, biological warfare bomblets and chemical warfare submunition payloads are carried by some “hit-to-kill” threats, and one or more of these bomblets or chemical submunition payloads can survive and cause heavy casualties even if the “hit-to-kill” vehicle accurately strikes the target.
Blast fragmentation type warheads are designed to be carried by existing missiles. Blast fragmentation type warheads, unlike “hit-to-kill” vehicles, are not navigable. Instead, when the missile carrier reaches a position close to an enemy missile or other target, a pre-made band of metal on the warhead is detonated and the pieces of metal are accelerated with high velocity and strike the target. The fragments, however, are not always effective at destroying the target and, again, biological bomblets and/or chemical submunition payloads may survive and cause heavy casualties.
A kinetic energy rod warhead has at least two primary advantages over “hit-to-kill vehicles” and blast fragmentation warheads. A kinetic energy rod warhead does not rely on precise navigation as is the case with “hit-to-kill” vehicles. Also, a kinetic energy rod warhead provides better penetration than blast fragmentation type warheads.
The primary components typically associated with a theoretical kinetic energy rod warhead are a projectile core or bay including a number of individual lengthy rod projectiles or penetrators, and an explosive charge. When the explosive charge is detonated, the rod projectiles or penetrators are deployed. Typically, these components are within a hull or housing.
The inventor hereof, Richard M. Lloyd, has published several textbooks concerning kinetic energy rod warheads, and including some discussions of “hit-to-kill” vehicles and blast fragmentation type warheads, and has been granted a number of patents for kinetic energy warheads and/or kinetic energy rod warhead technology, including U.S. Pat. Nos. 6,598,534; 6,779,462; 6,931,994; 7,040,235; 7,415,917; 7,017,496; 6,973,878; 6,910,423; 6,920,827; 7,624,682; 7,621,222; 7,624,683; and 7,143,698. The inventor hereof also has various pending patent applications concerning kinetic energy rod warheads and kinetic energy rod warhead technology, including U.S. Pat. Publ. Nos. 20060112847; 20070084376; and 20060283348.
Greater lethality is achieved when the projectiles or rods of a kinetic energy rod warhead are deployed to intercept and/or destroy a target. Some methods for aiming of fragments or projectiles is disclosed in various patents by others for various types of warheads or ordnance systems, including U.S. Pat. Nos. 4,026,213; 3,703,865; 3,757,694; 3,796,159; 2,925,965; and 4,216,720, and German patent publication number DE19524726. For the most part, however, these patents do not take into consideration the countervailing considerations of weight, explosive sections, and/or hardware configurations that must be accounted for in a kinetic energy rod warhead.
In order to aim and deploy the projectiles or rods of a kinetic energy rod warhead, the explosive charge is typically divided into a number of explosive charge segments or sections, with sympathetic shields between the segments. Each explosive segment may have its own detonator. Selected explosive charge segments are detonated to aim the projectiles in a specific direction and to control the spray pattern of the projectiles. For instance, detonators, detonator cords and/or jettison packs on one side of the projectile core can be detonated to cause their associated explosive charge segments to eject specified hull sections, creating an opening in the hull on the target side. Detonators on the opposite side of the core are detonated to deploy the projectile rods in the direction of the opening and thus towards the target. See e.g. U.S. Pat. Nos. 6,598,534 and 6,973,878 which are incorporated herein by reference.
A kinetic energy warhead including the foregoing design may be highly effective, but the exact position of the target in relation to the warhead explosive charge segments may affect aiming accuracy. The target may be positioned relative to the warhead such that the center of the rod set does not travel close to the target direction, which could result in aiming errors. For example, the target may be in a position where deploying one set of explosive segments, i.e. three adjacent segments, will result in the center of the rod core travelling in a direction which is not the target direction, but where deploying a different set of explosive segments, i.e. four adjacent segments, still may not direct the rods towards the target as desired. Additionally, the number of explosive segments detonated will affect the total spray pattern diameter, which may be critical in some applications.
To reduce potential aiming errors, explosive charge segments of a conventional kinetic energy rod warhead may be deployed in combinations to drive the rods in a specific deployment direction to more accurately strike a target, overcoming restrictions resulting from some hardware configurations. See e.g. U.S. Pat. Publ. No. 20070084376 which is incorporated herein by reference.
Even with such designs, however, hardware constraints may still inhibit the effectiveness of the kinetic energy rod warhead. In some cases, for example, the isolators or shields which divide the explosive into sections may interrupt explosive shock waves, and/or cause a decrease in the surface area of the explosive segments resulting in less available surface area for the shock waves to build. Moreover, it would be desirable to deploy an increased number of projectile rods towards a target for greater efficiency and lethality and/or to reduce the overall weight of the kinetic energy rod warhead.